/Engine/Source/Runtime/RenderCore/Public/RenderGraphUtils.h
Create and set up an 1D indirect dispatch argument from some GPU-side integer in a buffer (InputCountBuffer). Sets up a group count as (InputCountBuffer[InputCountOffset] * Multiplier + Divisor - 1U) / Divisor; Commonly use Divisor <=> number of threads per group.
namespace FComputeShaderUtils { FRDGBufferRef FComputeShaderUtils::AddIndirectArgsSetupCsPass1D ( [FRDGBuilder](API\Runtime\RenderCore\FRDGBuilder) & GraphBuilder, [ERHIFeatureLevel::Type](API\Runtime\RHI\ERHIFeatureLevel__Type) FeatureLevel, FRDGBufferRef & InputCountBuffer, const TCHAR * OutputBufferName, uint32 Divisor, uint32 InputCountOffset, uint32 Multiplier ) }